I recently received an ipad app as a .ipa file.
To install the app, i renamed it to .zip and fished out the app file and using the Iphone Configuration Utility was
I checked the provisioning profiles from my Entreprise account:
ProvisionsAllDevices
is present in all In House Distribution profiles. As far as I know, it's only available for Enterprise accounts:
Enrolled iOS Developers in the Enterprise program have the ability to distribute their in-house applications without the requirement of identifying individual devices or submitting the application to the App Store.
[...]
Please ensure to protect the distribution mechanism of this type of application as it can be installed on any Apple device if compromised.
(from the Developer Program User Guide — Enterprise Program)